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- TK!2
- =v
- #1
- :n
- h
- :v
- 10
- :s
- i
- :c
- Level of the ladders' crossing point
- #2
- :n
- L1
- :v
- 40
- :s
- i
- :c
- Length of the 1st ladder
- #3
- :n
- L2
- :v
- 30
- :s
- i
- :c
- Length of the 2nd ladder
- #4
- :n
- ya
- :s
- b
- :c
- Level of touch point (1st ladder)
- #5
- :n
- yb
- :s
- b
- :c
- Level of touch point (2nd ladder)
- #6
- :n
- w
- :s
- b
- :c
- Width of the alley
- #7
- :n
- w0
- :s
- b
- :c
- Final width vs. first guess ratio
- :f
- 1
- #8
- :n
- hmax
- :s
- b
- :c
- Maximum feasible level h
- #10
- :n
-
- :s
- b
- :c
- |<------ w ------->|
- #11
- :n
-
- :s
- b
- :c
- ya|\ |
- #12
- :n
-
- :s
- b
- :c
- | \ |
- #13
- :n
-
- :s
- b
- :c
- | \ L1 /|yb
- #14
- :n
-
- :s
- b
- :c
- | \ L2 / |
- #15
- :n
-
- :s
- b
- :c
- | \ / |
- #16
- :n
-
- :s
- b
- :c
- | /|\ |
- #17
- :n
-
- :s
- b
- :c
- | / | \ |
- #18
- :n
-
- :s
- b
- :c
- | / h| \ |
- #19
- :n
-
- :s
- b
- :c
- ----|/---------|------\|--
- =u
- =r
- #1
- :r
- " ********** LADDERS IN THE ALLEY **********
- :s
- C
- #2
- :r
- L1^2 = w^2 + ya^2 " There is an alley bounded by two high buildings.
- #3
- :r
- L2^2 = w^2 + yb^2 " Two ladders, L1 and L2 long, rest in corners and
- #4
- :r
- 1/h = 1/ya + 1/yb " lean against opposite buildings. What is w given h ?
- #6
- :r
- " The Iterative Solver has to be used. Guessing the unknown w usually leads
- :s
- C
- #7
- :r
- " to trouble because the interval of feasible guess values is too narrow.
- :s
- C
- #8
- :r
- " A reasonable guess depends on the magnitude of L1,L2,h; we may write it as
- :s
- C
- #10
- :r
- w/w0 = sqrt(min(L1,L2)^2 - (1/(1/h-1/max(L1,L2)))^2)
- #12
- :r
- " and assign w0=1 as the First guess. Now iteration is invoked automatically
- :s
- C
- #13
- :r
- " and always converges to a correct solution for any feasible L1,L2,h.
- :s
- C
- #15
- :r
- 1/hmax = 1/L1 + 1/L2 " This protects against trying too large a value for h:
- #16
- :r
- h = min(h,hmax) " error in this rule indicates infeasible data.
- %Tr,f,0,1,0,1,0
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